The invention relates to a data switching device comprising external ports for connection to the exterior, switching modules having switching ports connected to the external ports by means of a connections network.
Such a device is widely used for concentrating or switching data from terminals or modems.
This type of device is required to have a certain degree of insusceptibility to failure. Thus, failure of a single module should not cause the entire device to be rendered unserviceable and thereby inflict substantial nuisance on the external subscribers connected to the device.
The international Patent Application WO 90/13957 describes a device of this type in which steps have been taken to correct for failure of one of the modules; therefore, if a module fails a replacement module is called upon.
However, the procedure adopted in this known device has some drawbacks.
It is not certain that the replacement module is in good working order when put into operation.
It is necessary to provide a connection network for this auxiliary module, which becomes more difficult as the capacity of the switching device increases.